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Biomedical subjects

C Lu

Publications and source records attributed to C Lu.

At least 217 records · Page 12Linked to original sources
PubMed1995

[Repair of scalp defects with skull exposure].

The methods for repairing scalp defects and skull exposure are introduced. From 1980 to 1991, 9 cases of scalp defects and skull exposure from injury or tumor extirpation were treated with free omentum transfer with split skin graft, free flap or axial flap transfer. The surgical procedure was described in detail. For the whole defect of scalp with skull exposure the authors consider the free anterior-lateral femoral flap more appropriate and suggest that the free omentum flap be avoided as far as possible.

Adolescent↗
PubMed1995

[Diagnosis and treatment of primary ureteral carcinoma--a report of 12 cases].

Twelve cases with primary ureteral carcinoma are reported with a review of literatures. Urography was the main method of diagnosis, and retrograde uretero-pyelography was more helpful. Cystoscopy was mandatory before operation. CT was useful for diagnosis and staging. If needed, ureteroscopy could be used to increase diagnostic accuracy. The traditional total nephroureterectomy with a cuff excision of the urinary bladder was the first and basic choice of treatment. Regular cystoscopy, excretory urography and adjuvant intravesical therapy should be carried out after operation.

Aged↗
PubMed1995

[Application of T-subgroup cells assay in the immunology of oral-maxillofacial cancer].

We report on T-subgroup cells in 70 cases of oral-maxillofacial cancer determined by T-monoclone antibody-OKT system. The results are as follows: CD3, CD4/CD8 value of cancer patients was decreased significantly, compared with that of health or oral benign tumor patients. CD8 was significantly increased (P < 0.001); however, CD8 was decreased and CD4/CD8 ratio was increased after operation. 20 cases underwent the dynamic testing, determined in 1 week, 1 and 3 month. The results are as follows: CD3, CD4, CD4/CD8 values were increased gradually and CD8 was decreased gradually in 17 cases of curative patients, but CD4, CD4/CD8, values were decreased and CD8 was increased significantly in 3 cases of metastased patients. Our conclusion is that determination of T-subgroup cells is of reference value for monitoring and treating cancer patients.

Adenocarcinoma↗
PubMed1995

Constitutive expression and modulation of the functional thrombin receptor in the human kidney.

Thrombin exerts procoagulant effects and has also many cellular effects mediated by cell surface receptors. A functional thrombin receptor from human platelets has been cloned and sequenced. In the present study, by reverse transcription and polymerase chain reaction, using specific primers designed from the thrombin receptor cDNA sequence, we show that the mRNA encoding for this receptor can be amplified from freshly isolated human glomeruli obtained by microdissection of normal kidney cortex. By immunohistochemistry using a specific monoclonal antibody, ATAP2, directed against the extracellular N-terminus of this receptor, we find that this functional thrombin receptor is constitutively expressed in the normal human kidney. The three glomerular cell types, endothelial, mesangial, and epithelial cells, were positively stained, as were the endothelial cells of renal arteries, arterioles, venules, and peritubular capillaries. Occasionally, interstitial cells and smooth muscle cells in the media of renal arteries were also stained. Proximal and distal tubular cells were not stained. By in situ hybridization, using a digoxigenin-labeled cDNA probe specific for thrombin receptor, the thrombin receptor mRNA was found to have the same distribution as the thrombin receptor protein detected by immunohistochemistry. A lighter staining of glomerular endocapillary cells was observed in cases of thrombotic microangiopathy and extracapillary glomerulonephritis, two renal diseases associated with in situ thrombin generation and fibrin formation. In one case of thrombotic microangiopathy, we observed an increase in thrombin receptor mRNA. This suggests that thrombin receptor protein is not always correlated with thrombin receptor mRNA level. Internalization and degradation of thrombin receptor protein have been demonstrated in vitro and could also occur after activation in vivo. This is the first demonstration of the constitutive expression of the functional thrombin receptor in the human kidney. These results suggest that thrombin may exert glomerular and vascular effects within the kidney in normal and in pathological conditions.

Amino Acid Sequence↗
PubMed1995

Developmental activity variations of DNA polymerase alpha, delta, epsilon in mouse forebrains and spleens.

The levels of DNA polymerase alpha, delta, epsilon were examined in the neonatal mouse forebrains and spleens. The levels of DNA polymerase alpha were determined by the difference of polymerase activity in the absence and the presence of alpha specific inhibitor, BuPdGTP, or its monoclonal antibody. The levels of DNA polymerase delta were determined in H.A fractions after separating it from the other two enzymes. The levels of DNA polymerase epsilon were identified in H.A fractions by the use of alpha-monoclonal antibody or BuPdGTP. Results showed that in the mouse forebrain DNA polymerase alpha, delta, epsilon activities are the highest before birth, decline sharply following birth and are very low on the 8th day and hardly detectable on the 17th day; as for the mouse spleen, however, DNA polymerase alpha, delta, epsilon activities are the lowest at birth, increase rapidly after birth and reach their maxima on the 8th day and then decline gradually but remain in higher levels. These results not only prove that DNA polymerase alpha and delta take part in cell DNA replication but also suggest that DNA polymerase epsilon is involved in DNA replication.

Animals↗
PubMed1995

DNA content and morphological parameters in synovial sarcoma and synovioma.

By using image analysis technique with 6 normal synovial tissue specimens as controls, nuclear DNA content and morphological parameters in specimens from 51 synovial sarcomas and 15 synovioma were examined quantitatively. The DNA content in synovial sarcoma and synovioma was significantly different (P < 0.01), and that of synovioma and normal synovial tissue was also different (P < 0.05). Morphological parameters including nuclear areas and perimeters differed significantly among the above three groups (P < 0.01). There was no correlation between the DNA content of synovial sarcoma and its histologic type (P > 0.05), but the DNA content greatly differed between its higher and lower differentiated grade in each type (P < 0.01). The DNA content in synovial sarcoma IIA stage, according to Enneking's staging system was lower than that in IIB, IIIA and IIIB (P < 0.05). The 5-year survival rate of synovial sarcoma with diploid/nearly diploid (D/ND) pattern was higher than that of aneuploid (AN) pattern (P = 0.028). The study suggests that analysis of the DNA content and morphological parameters of tumor cells is helpful in the diagnosis and pathologic grading of synovial sarcoma. It also provides a guide to clinical operation and estimation of the prognosis. Although synovioma is usually a well-differentiated and benign lesion, this investigation also suggested that increased DNA content may be an indication of poor prognosis for this neoplasm.

Adolescent↗
PubMed1995

[Determination of procollagen III levels in serum and broncho-alveolar lavage fluid in patients with interstitial lung disease and its clinical significance].

Serum and broncho-alveolar lavage fluid (BALF) levels of procollagen III (PCIII) were determined in 26 patients with interstitial lung disease (ILD) and healthy subjects as controls. The results showed: (1) Levels of PCIII in serum and BALF were significantly higher in the patient group than those in the control group; (2) A highly positive correlation was found between PCIII levels and alveolar macrophage counts in BALF in the patient group. (3) PCIII level in BALF (albumin as a denominator) is higher than that in own serum both in control and patient group, the higher level of PCIII in BALF might be the result of local production. We are of the opinion that changes of PCIII level in serum and BALF might be helpful in the evaluation of the turnover of collagen in the lung.

Adult↗
PubMed1995

[Production and characterization of monoclonal antibody against aflatoxin B1].

Two hybridoma cell lines 1B5 and 2F1 capable of secreting specific monoclonal antibodies (McAbs) against aflatoxin B1 (AFT B1) were obtained. BALB/c mice were immunized by intrasplenic injection of AFT B1-human serum albumin conjugate (AFT B1-HSA) containing 9 AFT B1 residue per molecule. Spleen cells of BALB/c mouse with high serum antibody titer were fused with SP 2/0 myeloma cells in the presence of polyethylene glycol. Hybridoma cell lines were selected by using an indirect ELISA with AFT B1-keyhole limpet haemocyanin as coating antigen and grown as ascite tumour cells in BALB/c mice which previously had received an intraperitoneal injection with Freund's incomplete adjuvant. The McAbs were found to have strong reaction with AFT B1-bovine serum albumin conjugate (AFT B1-BSA) and no reaction with HSA or BSA. The reactivity of the McAbs with AFT analogs was determined by an indirect inhibition ELISA and the concentrations (ng/ml) required to inhibit 50 binding of McAb to AFT B1-BSA conjugate solid phase were AFT B1 4.0ng/ml, B2 36.9ng/ml, G1 23.3ng/ml and G2 403.3ng/ml for 1B5 McAb, and AFT B1 2.4ng/ml, B2 2.6ng/ml, G1 2.8ng/ml and G2 4.7ng/ml for 2F1 McAb.

Aflatoxin B1↗
PubMed1995

[Correlation between roentgenogram and CT scans with the changes of cells in bronchoalveolar lavage fluid in sarcoidosis].

Considering protean and variability of chest findings of sarcoidosis, the correlation between finding on roentgenogram and CT scans with changes of total, differential cell count and subsets of lymphocytes of BALF in 25 cases with sarcoidosis was studied. The results showed that CT could detect more groups of enlarged lymph nodes in the mediastinum and more minimal lesions in lung parenchyma in those patients who showed stage 0 and I on chest roentgenogram. The parenchymal changes were distributed mainly among the bronchovascular sheath. Good correlation was found between findings on CT scan and total cell count in BALF. Fibrotic changes on CT scan were usually associated with an increase in neutrophils of BALF. It indicated that CT could more precisely assess the lesions in the mediastinum and lung parenchyma and be served as an important supplementary diagnostic measure to roentgenogram for patients with sarcoidosis.

Bronchoalveolar Lavage Fluid↗
PubMed1994

Sequential folding of UmuC by the Hsp70 and Hsp60 chaperone complexes of Escherichia coli.

Replication-blocking lesions generate a signal in Escherichia coli that leads to the induction of the multigene SOS response. Among the SOS-induced genes are umuD and umuC, whose products are necessary for the increased mutation rate in induced bacteria. The mutations are likely to result from replication across the DNA lesion, and such a bypass event has been reconstituted in vitro (Rajagopalan, M., L, C., Woodgate, R., O'Donnel, M., Goodman, M. F., Echols, H. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 10777-10781). In this work, we show that the chaperone proteins promote the proper folding of UmuC protein in vitro. We treated purified and inactive UmuC with Hsp70 and Hsp60. After Hsp70 treatment, the DNA binding activity of UmuC was recovered, but the ability to promote replication across DNA lesions was not. However, lesion bypass activity was recovered upon further treatment with Hsp60. The biological significance of such a folding pathway for UmuC protein is strengthened by in vivo evidence for a role of DnaK in UV-induced mutagenesis.

Bacterial Proteins↗
PubMed1994

Echocardiographic diagnosis of congenital absence of the pericardium in a patient with VATER association defects.

The VATER association denotes a nonrandom pattern of congenital malformations which typically include vertebral defects, anal atresia, tracheo-esophageal fistula, and radial and renal dysplasia. Vascular anomalies including ventricular septal defect and single umbilical artery have also been described, although the frequency of cardiovascular anomalies in this congenital association is unknown. In this report, we describe a 26-year-old patient with several VATER association defects who, in addition, was found to have congenital absence of the left pericardium and an aberrant right subclavian artery.

Abnormalities, Multiple↗
PubMed1994

Progressive loss of sensitivity to endothelium-derived growth inhibitors expressed by human melanoma cells during disease progression.

Tumor progression is frequently associated with changes in responsiveness of tumor cells to paracrine growth factors. A potential major source of such paracrine factors in solid tumors are endothelial cells since this type of cell can constitute a sizeable fraction of the cellular composition of solid tumors. As an initial step to examining the possible effects of endothelial cell-associated growth factors on tumor cell growth, a panel of human melanoma cell lines representative of different stages of tumor progression was employed for studies utilizing endothelial cell-derived growth modulators. Macrovascular or microvascular human endothelial cells from umbilical vein or from skin, respectively, inhibited melanoma cell growth in direct coculture experiments. The potency of this inhibitory effect diminished as a function of melanoma progression. Conditioned media from endothelial cell cultures mimicked the effect of the cell coculture experiments, suggesting the involvement of soluble growth factor(s). Approximately 50-75% of the conditioned media inhibitory effect was abrogated by addition of the neutralizing antibody to interleukin-6 (IL-6). Gel filtration chromatography revealed the presence of additional inhibitors in endothelial cell conditioned medium. Two peaks of activity were detected with apparent molecular weights of approximately 100-150 Kd and 20-30 Kd, the latter containing IL-6 activity. Whereas early-stage radial growth phase (RGP) primary tumor-derived melanoma cells were sensitive to at least three different endothelial products of high or low molecular weight (including IL-6), melanoma cells from more advanced metastatic lesions were resistant to the latter activities, and retained only partial sensitivity to the high molecular weight inhibitor. More advanced vertical growth phase (VGP) primary melanoma cell lines expressed intermediate inhibition-sensitive phenotypes. Thus human melanoma development appears to be associated with progressive loss of sensitivity to the growth inhibitory effects of IL-6 and other factors produced by endothelial cells. This is likely to be a result of a selection process when tumor cells are confronted with adjacent vasculature during the progress of tumor angiogenesis.

Cell Division↗
PubMed1994

Postnatal changes in the G-proteins, cyclic nucleotides and adenylyl cyclase activity in rabbit heart cells.

We have studied the postnatal changes in the levels of isoforms of stimulatory (Gs) and inhibitory (Gi) G-proteins, cAMP and cGMP in washed particulate membranes (WPM) from whole ventricles as well as from isolated ventricular myocytes and have also measured adenylyl cyclase (AC) activity in WPM prepared from isolated myocytes of adult (AD) and newborn (NB) rabbit heart. Immunoblot analysis for the levels of Gi alpha 1, G alpha 2, Gi alpha 3 and Gs alpha subunits showed that Gi alpha 2 and Gi alpha 3 were higher in WPM from whole ventricles of NB compared to AD. This ratio was much higher in WPM from isolated ventricular myocytes since Gi alpha 2 and Gi alpha 3 were either absent or present in extremely low immunodetectable levels in WPM from AD ventricular myocytes. Gi alpha 1 levels were not different for AD compared to NB WPM, whether prepared from whole ventricle or from isolated myocytes. Two forms of Gs alpha, a small form (Gs alpha-S) and a large form (Gs alpha-L), were immunodetected at 43 and 48 kDa, respectively. The Gs alpha-S form was higher in AD WPM and the Gs alpha-L form was higher in NB WPM while the total Gs alpha(L+S) was not different. The Gs alpha results for WPM from isolated myocytes were not different from the results for WPM from whole ventricles. Basal levels of cAMP were 80% higher in NB compared to AD whole ventricles and were 200% higher in NB compared to AD isolated myocytes. Levels of cGMP were 4-5 fold higher in NB than in AD myocytes and ventricular tissue. Basal AC activity was higher in NB than in AD WPM from isolated myocytes and was enhanced by Gpp(NH)p pretreatment in AD but not in NB WPM. The isoproterenol-induced increase in AC activity was higher in AD compared to NB WPM and was completely abolished by Gpp(NH)p pretreatment in NB but not in AD WPM. Forskolin caused a greater increase in AC activity in NB than in AD WPM. The post-natal decrease in the levels of Gi alpha 2 and Gi alpha 3, particularly in isolated ventricular myocytes, may help to explain the smaller effects of isoproterenol and greater muscarinic influence on ICa, as we previously showed, and the smaller effect of isoproterenol on AC activity in NB compared to AD WPM.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenylyl Cyclases↗
PubMed1994

Developmental changes in the actions of phosphatase inhibitors on calcium current of rabbit heart cells.

We used whole-cell voltage clamp to compare the modulation of calcium current density (ICa, picoampere per picofarad) of freshly isolated, adult and newborn rabbit heart in response to intracellular application of microcystin and okadaic acid, both of which block phosphatase activity of phosphatase type 1 and 2A. Newborn cells showed a much larger response to the intracellular application of either microcystin or okadaic acid than did adult cells. In newborn cells, the application of microcystin produced an increase in ICa which appeared to maximize ICa, as shown by the rise in ICa to levels which could be reached by application of 10 microM forskolin or by the intracellular application of 200 microM 3',5'-cyclic adenosine monophosphate (cAMP). In adult cells, the maximal response to microcystin was considerably less than that obtainable with forskolin or cAMP. After achieving a maximal response with microcystin, the addition of forskolin increased ICa further in adult cells but elicited no additional response in newborn cells. The treatment of cells with 0.1 microM isoproterenol, a concentration approximately equal to that required for a half-maximal response, strongly potentiated the effect of microcystin in newborn cells, but not in adult cells. We propose that newborn rabbit heart cells compared with adult rabbit heart cells have a greater level of protein phosphatase activity (perhaps combined with a somewhat greater kinase activity), a greater proportion of the protein phosphatase activity in the form of protein phosphatase type 1 (which is inhibited by isoproterenol) and a greater dependence on the inhibition of protein phosphatase as a mechanism of action of isoproterenol, compared with the increase in kinase activity on calcium channels.

Animals↗
PubMed1994

Dynamic imaging of obstructed opossum esophagus. From altered load to altered contractility.

We studied by barium contrast the dynamics of experimental obstruction in the opossum esophagus. Immediately after banding the gastroesophageal junction, entrapment of the bolus between the band and the peristaltic contraction led to esophageal bulging, forceful retropulsion of the bolus at the band, and the repeated triggering of peristaltic contractions by the retropelled bolus. In ensuing weeks, triggering of contractions became more difficult and contractions led to bizarre "corkscrew" movements of the increasingly distended and tortuous esophagus. A tight contraction ring that moved very slowly retrograde was occasionally observed in the chronically distended esophagus. Computer-assisted analysis showed that the area and perimeter of the bolus were abnormally large in chronic obstruction and that during its passage through the esophagus the compactness of the bolus increased no longer. Configurational analysis of the cone that the peristaltic contraction shapes at the tail of the barium column showed this to narrow progressively on passage through the normal esophagus and, paradoxically, to widen in both acute and chronic obstruction.

Animals↗
PubMed1994

Effects of lead on root growth, cell division, and nucleolus of Allium cepa.

The effects of different concentrations of lead nitrate on root growth, cell division, chromosome morphology and nucleolus in root tip cells of Allium cepa were studied. The concentrations of lead nitrate (Pb(NO(3))(2)) were 10(-7), 10(-6), 10(-5), 10(-4), 10(-3) and 10(-2) m. It was observed that lead reduces root growth and causes mitotic irregularities, including c-mitosis, anaphase bridges, and chromosome stickiness. Also, interphase cells with micronuclei, irregularly shaped nuclei and nuclei with decomposed nuclear material were noticed. The c-mitotic effect reached its maximum in the meristem at above 10(-4) m Pb, when practically almost all the anomalous dividing cells are of this type. After treatment with Pb, there were many similar silver-stained particulate materials scattered in the nucleus in short, rounded meristem cells and in long, oblong root cap cells.

Journal Article↗